To the contrary, section 3202 provides that the workers' compensation laws shall be "liberally construed by the courts with the purpose of extending their benefits for the protection of persons injured in the course of their employment." (§ 3202; see Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096 [ 78 Cal.Rptr.2d 500].) (13) The legislative history and development of the statute clearly show the Legislature was concerned with the unfairness to firefighters and peace officers who, while exposed to carcinogens during the course of their job duties, nonetheless were denied benefits because it was not possible to prove the genesis of the cancer.

) We cannot reweigh evidence or decide disputed questions of fact. ( Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096 [ 78 Cal.Rptr.2d 500].) "It is within the province of the WCAB to make the factual determination as to whether an employee has knowledge of an industrial related injury and, if so, when that knowledge arose. [Citation.] An appellate court `will not interfere with the board's factual findings if they are supported by substantial evidence or by reasonable inferences drawn from the testimony adduced.

Should the Board decide on remand that former section 4062 is applicable, the repealed version of the statute should not be applied. See Gee v. Workers' Comp. Appeals Bd. (2002) 96 Cal.App.4th 1418, 1426-1427 [ 118 Cal.Rptr.2d 105]; Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096 [ 78 Cal.Rptr.2d 500]. This conclusion is also consistent with section 47 of Sen. Bill 899, which states in part: "The amendment, addition, or repeal of, any provision of law made by this act shall apply prospectively from the date of enactment of this act, regardless of the date of injury, unless otherwise specified . . ." (Underscoring added.)

We agree "that the presumption in section 4062.9 was intended to affect the burden of proof because it was part of an effort by the Legislature to implement a public policy of reducing medical-legal costs and expediting resolution of medically related issues by restricting the number of medical evaluations." ( Davis v. Interim Healthcare, supra, 65 Cal. Comp. Cases at p. 1043, citing Minniear v. Mt. San Antonio Community College District, supra, 61 Cal.Comp. Cases at pp. 1059-1060; see also Kuelen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096.) Accordingly, the treating physician's presumption imposes upon the party against whom it operates the burden of proof as to the nonexistence of the presumed fact.

[Citation.] Questions of statutory interpretation are, of course, for this court to decide. [Citations.]"' [Citations.]" (Keulen, Jr. v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1095-1096.) 2. Rushing was discharged from Glousman's care and could not change physicians.

The WCJ may have been referring to Tyler v. Workers' Comp. Appeals Bd. (1997) 56 Cal.App.4th 389 [ 65 Cal.Rptr.2d 431], in which this Division interpreted sections 5701 and 5906 as authorizing a WCJ, or the WCAB, to order further development of the record at any time during the proceedings, including obtaining additional medical evidence concerning the finding of injury, to enable a complete adjudication of the issues consistent with due process. (See also Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089 [ 78 Cal.Rptr.2d 500], M/A Com-Phi v. Workers' Comp. Appeals Bd. (1998) 65 Cal.App.4th 1020 [ 76 Cal.Rptr.2d 907], and McClune v. Workers' Comp. Appeals Bd. (1998) 62 Cal.App.4th 1117 [ 72 Cal.Rptr.2d 898].) However, Tyler explained this could not include an independent medical examination for injuries occurring after January 1, 1991.

And Dr. Grahek specifically directed Lowery—and the District—that Lowery "is restricted from heavy lifting . . . ." Faced with Dr. Grahek's explicit work restrictions fixing a 30-pound maximum for lifting and carrying, with lower limits depending on frequency, and limiting his climbing, stooping, kneeling, crouching, crawling, and twisting activities, the District could not conclude that Lowery was capable of more. (Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096-1097 [Evidence from lay witness is not substantial evidence; medical proof is required on diagnosis, prognosis and treatment].) It could not place Lowery in a position that required functions and tasks that his doctor had expressly forbidden him to perform.

And Dr. Grahek specifically directed Lowery—and the District—that Lowery "is restricted from heavy lifting . . . ." Faced with Dr. Grahek's explicit work restrictions fixing a 30-pound maximum for lifting and carrying, with lower limits depending on frequency, and limiting his climbing, stooping, kneeling, crouching, crawling, and twisting activities, the District could not conclude that Lowery was capable of more. (Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096-1097 [Evidence from lay witness is not substantial evidence; medical proof is required on diagnosis, prognosis and treatment].) It could not place Lowery in a position that required functions and tasks that his doctor had expressly forbidden him to perform.

It is within this court's duty to decide, however, whether the undisputed facts and those found by the WCAB, which are supported by substantial evidence, fall within the ambit of a statutory provision. ( Keulen v. Workers' Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1096, 78 Cal.Rptr.2d 500.) Where, as here, the meaning and application of a statute is in dispute, our first task “is to ascertain the intent of the Legislature so as to effectuate the purpose of the law.”

We therefore may not reweigh evidence or decide disputed questions of fact, and instead “must determine whether the evidence, when viewed in light of the entire record, supports the award of the WCAB.” (Keulen v. Workers’ Comp. Appeals Bd. (1998) 66 Cal.App.4th 1089, 1095-1096.) Questions of law, however, are for this court to decide, yet we “nevertheless accord ‘“significant respect”’ to the WCAB’s interpretation of workers’ compensation statutes ‘“unless clearly erroneous.”